The present invention relates to a method for associating a transmitter which transmits at least one item of communication information in car-to-car communication with an object described by environmental data of at least one environmental sensor in a receiving motor vehicle.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
In the state-of-the-art, systems have been proposed in which motor vehicles can wirelessly exchange items of communication information with each other or with infrastructure devices, in particular via radio transmission. Such exchange of data between motor vehicles and the infrastructure is referred to as car-to-car communication (C2C communication) in the specific situation of communication between motor vehicles, or as motor-vehicle-to-X-communication (C2X communication) in general situations. Standards for the exchanged items of communication information as well as for the radio communication itself have already been defined and are generally known in the art.
For example it is known to transmit as communication information the GPS position and/or the speed of a motor vehicle to other motor vehicles in the vicinity which are configured for car-to-car communication. Vehicle systems which receive the communication information from other motor vehicles via the radio channel and additionally know their own GPS position can calculate based on transformations, for example a UTM-transformation, the relative distances between the own receiving motor vehicle and the surrounding transmitting road users in a two-dimensional coordinate system. Thus, the car-to-car communication can figuratively speaking be modeled as a “sensor” which like actual environmental sensors of a motor vehicle, for example radar sensors, cameras, laser sensors and the like, detects the objects in its environment and measures their relative distances and speeds.
In the state-of-the-art, vehicle systems are also known which associate the communication information or communication objects received via the car-to-car communication with environmental data supplied by an environmental sensor. For example, environmental models are used in which the relative position of other objects is entered, wherein additional items of information can be associated with each of these objects, for example the relative speed and/or other properties of the object. Such environmental models can be enhanced with additional items of information relating to other vehicles by using the communication information, in particular those items of information that cannot be measured purely based on environmental sensors of the receiving motor vehicle. The masses of other motor vehicles, stiffness and the like are examples for such additional items of information.
For enabling such an association, it must first be determined with which object that is detected by the environmental sensors and that is described by the environmental data, a transmitter (a transmitting device) which has provided the communication information is associated. As described above, it is known in the art to determine a relative position and speed of the motor vehicle having the transmitter, hereinafter also referred to a s a host vehicle, from a GPS position and a transmitted speed as a car-to-car communication object. Relative positions and speeds of the environmental-sensor-objects that are detected by the environmental sensors are also known from the environmental data. These relative positions and speeds can now be compared for example by analyzing a Mahalanobis distance. When the environmental-sensor-object with which the sensor can be associated is identified, items of information from other vehicles contained in the items of communication information can accordingly be associated with this environmental-sensor-object.
The comparison of the relative positions originating from the same object (motor vehicle) but from different sources of information, namely the car-to-car information and the environmental sensors, is an important aspect for a successful comparison of data. While an environmental sensor can measure such relative positions very accurately, the calculation of the relative positions via the car-to-car communication is based on GPS-coordinates which according to the methods known to date can only be determined with insufficient accuracy.
Consequently, data received from another motor vehicle via the car-to-car communication and data determined by the environmental sensor from a corresponding object do not appear to belong together. An association would then erroneously not be possible because the relative distances or the relative positions do not match due to the inaccurate GPS data.
It would therefore be desirable and advantageous to provide an improved method to enable a more accurate and more reliable association of a transmitter with an object that is detected by environmental sensors in a receiving motor vehicle.